My U.S. Pat. No. 4,896,512, which is assigned to the same assignee as the present application, improves upon the efficiency of a compartmentalized, multi-temperature transport refrigeration system by causing a remote evaporator requiring heat to function as a condenser for an evaporator requiring cooling. Thus, instead of rejecting heat in the normal condenser function, the normal condenser is by-passed. Hot gas leaving the compressor discharge port is directed into a remote evaporator requiring heat, and the refrigerant leaving the remote evaporator is directed to the host liquid line, eg., the receiver. The refrigerant then proceeds to the evaporator which requires cooling.
While this arrangement greatly facilitates a heating cycle in a remote compartment, without the necessity of employing costly induction alternators to power electrical resistors, the arrangement is somewhat inflexible, as the host evaporator must always serve as the low temperature compartment. In other words, a frozen cargo or load must always be placed in a compartment directly adjacent to the host refrigeration unit, and a fresh load must always be in a remote compartment.
It would be desirable, and it is an object of the present invention, to increase the flexibility of a compartmentalized, multi-temperature transport refrigeration system, without the necessity of requiring auxiliary electrical power and associated resistors.